There has been known a conventional automatic working device that automatically determines the type of a target workpiece and performs an assembly operation, a processing operation, or the like on the target workpiece. The automatic working device is generally provided with a dedicated sensor to determine the type of a workpiece. This technique has been known as disclosed in, for example, Japanese Laid-open Patent Publication No. H10-15865.
However, because the conventional automatic working device requires to include a dedicated sensor in order to determine the type of a workpiece, there is a problem in that a cost is high.